[mapserver-users] queryByShape returns too many results

[Lime, Steve D (MNIT)]

You don't use the nextShape() method to retrieve shapes as a result of a query. Here's the pseudo code:

$layer->queryByShape($q_shape);
for($i=0; $i < $layer->getNumResults(); $i++) {
  $shape = $layer->getShape($layer->getResult($i));
  .. do something with the shape ..
}

As part of query operations the bounding box of $q_shape was used to select candidate shapes (that's why nextShape() is returning what is does).

Steve



________________________________
From: mapserver-users-bounces at lists.osgeo.org [mapserver-users-bounces at lists.osgeo.org] on behalf of Bistrais, Bob [Bob.Bistrais at maine.gov]
Sent: Wednesday, February 20, 2013 2:38 PM
To: mapserver-users at lists.osgeo.org
Subject: [mapserver-users] queryByShape returns too many results

I am working on a spatial query module (actually, modifying an existing GeoMoose module) which uses queryByShape to take a previously selected feature from one layer, and use it to select features from another layer.  Both layers are shapefiles, the query layer is of course polygon, the selection layer is points in this case.

When I do the query I am finding too many results are returned- there are many features outside the query polygon which are selected, well beyond the polygon boundary.   The selected features might possibly be within the BBOX of the polygon, but I only want what’s within the polygon.


                $layer->queryByShape($q_shape);
                while($shape = $layer->nextShape()) {
                                # if we have a projection, convert the shape into latlong
                                if($q_shape->intersects($shape) == MS_TRUE or $shape->containsShape($q_shape) == MS_TRUE) {
                                                if($projection != NULL) {
                                                                $shape->project($projection, $LATLONG_PROJ);
                                                }
                                                $foundShapes[] = $shape;
                                }
                }


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